Hearing Loss and Dementia

Hearing and the Brain

Our brains take in information about the world through our senses – and our sense of hearing is one of the main channels. From audio information gathered by our hearing, we interact with and respond to the world around us.

Did you know that hearing actually happens in the brain? Sound waves are picked up by the outer ear and travel through the middle and inner ear, where they are transformed into electric signals to be processed by our brains. When we get songs stuck in our heads or we jolt awake from our alarm, it is because our brains have remembered these sounds from multiple exposures.

Imagine how detached and unsettled one would feel if our hearing abilities changed. Hearing loss affects approximately 20% of Americans, with one-third of people over the age of 65 experiencing some degree of hearing impairment. Presbycusis, or age-related hearing loss, is a natural process that occurs with aging. Noise-induced hearing loss is a form of acquired hearing loss, which occurs due to exposure to loud sounds. Regardless of the form, a number of studies in recent years have found links between hearing loss and cognitive decline.

Studies on Hearing Loss and Dementia

Over the past decade, researchers at Johns Hopkins University have linked untreated hearing loss with an increased risk for developing dementia. According to Frank Lin, lead researcher in the Johns Hopkins studies, “The general perception is that hearing loss is a relatively inconsequential part of aging.” Along with his team, studies have revealed otherwise.

A 2011 study from Johns Hopkins found that older Americans “with hearing loss are significantly more likely to develop dementia over time than those who retain their hearing…the findings could lead to new ways to combat dementia, a condition that affects millions of people worldwide and carries heavy societal burdens.” In this study, Lin and his team of researchers tracked 639 test subjects with normal, healthy cognitive ability at the beginning of the study, for 12 to 18 years. Through the course of the study, subjects took period hearing tests. Researchers found that there was a correlation between the subject’s hearing abilities and their cognitive abilities: “a common pathology may underlie both [hearing loss and dementia] or that the strain of decoding sounds over the years may overwhelm the brains of people with hearing loss, leaving them more vulnerable to dementia.”

While our brain tissue mass naturally decreases as we age, there is an added strain with untreated hearing loss. This leads to a heavier cognitive load. In another study from Johns Hopkins, Lin and his team tracked for six years the cognitive abilities for 2,000 older adults (average age of 77). Twenty-four percent of test subjects were more likely to have diminished cognitive decline when experiencing untreated hearing loss, compared to subjects with normal hearing.

However, it is not all bad news, according to Lin, who believes that these studies “may offer a starting point for interventions – even as simple as hearing aids – that could delay or prevent dementia by improving patients’ hearing.” By using hearing aids, better access to sound could lighten the “cognitive load,” while empowering people to remain connected to their loved ones, colleagues, and communities.

The Benefits of Hearing Aids

The use of hearing aids has been found in various studies to support cognitive function.

In one study from France, which spanned 25 years, researchers reported that “the use of hearing aids almost eliminates this cognitive decline. By at least partially restoring communication abilities, hearing aids may help improve mood, increase social interactions and enable participation in cognitively stimulating abilities and consequently could slow cognitive decline.”

Similarly, a 2011 study from Japan revealed that hearing aids bring significant benefits to one’s cognitive functions. In a small test group of 12 participants, researchers recorded annual auditory and cognitive examination for three years. Researchers found that the “prescription of a hearing aid during the early stages of hearing loss is related to the retention of cognitive abilities in such elderly people.”

Seeking Treatment for Hearing Loss

“Blindness separates people from things. Deafness separates people from people.” – Helen Keller

The same could be said of untreated hearing loss. According to the Hearing Loss Association of America, people with untreated hearing loss experience challenges with verbal communication and thus avoid social gatherings. Research on dementia has shown that people who are more social are less likely to develop dementia, due to consistent engagement with the world around them.

By treating hearing loss with the use of hearing aids, you reduce your potential for developing dementia, while staying connected to your loved ones, your favorite activities, and the world around you.